代码随想录算法训练营第55天｜583. 两个字符串的删除操作，72. 编辑距离

583. 两个字符串的删除操作

class Solution {
public:
    int minDistance(string word1, string word2) {
        int m = word1.size();
        int n = word2.size();
        vector> dp(m + 1, vector(n + 1));

        for (int i = 1; i <= m; ++i) {
            dp[i][0] = i;
        }
        for (int j = 1; j <= n; ++j) {
            dp[0][j] = j;
        }
        for (int i = 1; i <= m; i++) {
            char c1 = word1[i - 1];
            for (int j = 1; j <= n; j++) {
                char c2 = word2[j - 1];
                if (c1 == c2) {
                    dp[i][j] = dp[i - 1][j - 1];
                } else {
                    dp[i][j] = min(dp[i - 1][j], dp[i][j - 1]) + 1;
                }
            }
        }

        return dp[m][n];
    }
};

72. 编辑距离

class Solution {
public:
    int minDistance(string word1, string word2) {
        int n = word1.length();
        int m = word2.length();

        if (n * m == 0) return n + m;

        vector> D(n + 1, vector(m + 1));

        for (int i = 0; i < n + 1; i++) {
            D[i][0] = i;
        }
        for (int j = 0; j < m + 1; j++) {
            D[0][j] = j;
        }

        for (int i = 1; i < n + 1; i++) {
            for (int j = 1; j < m + 1; j++) {
                int left = D[i - 1][j] + 1;
                int down = D[i][j - 1] + 1;
                int left_down = D[i - 1][j - 1];
                if (word1[i - 1] != word2[j - 1]) left_down += 1;
                D[i][j] = min(left, min(down, left_down));

            }
        }
        return D[n][m];
    }
};